Objective: Mesenchymal stem cells (MSCs) have potential in orthopaedic applications as they are able to differentiate into bone and cartilage. These cells can be isolated from a variety of adult tissues. Three sources that are relevant for orthopaedic applications are bone marrow, periosteum and adipose tissue. The purpose of the present study was to compare the growth kinetics and colony forming potency of rat MSCs from these sources.
Material and Method: Bone marrow from the femur, periosteum from the femoral diaphysis and adipose tissue from the inguinal area of Wistar rats were harvested for MSC isolation. The cells from 2nd-4th passage from primary culture were selected for study of their growth curves, population doubling time and colony forming ability using the percentage of colony forming units and colony forming area as the outcome measure.
Results: The isolated cells from these 3 sources were capable of osteogenesis, chondrogenesis and adipogenesis. The growth kinetics were compared using the growth curve and the population doubling time (PDT): bone marrow derived cells (PDT = 3.99 days, SD = 1.19) and periosteum derived cells (PDT = 3.55 days, SD = 1.21) had faster growth kinetics than adipose derived cells (PDT = 4.65 days, SD = 1.53). The percentage of colony forming units and the colony forming area from bone marrow derived cells (% colony forming unit = 8.58, SD = 1.35 and % colony forming area = 25.12, SD = 7.31) and periosteum derived cells (% colony forming units = 9.92, SD = 2.06, % colony forming area = 32.45, SD = 10.74) were significantly greater (p < 0.05) than adipose derived cells (% colony forming units = 5.92, SD = 0.78, % colony forming area = 15.80, SD = 9.035).
Conclusion: The growth kinetics and colony forming potency of MSCs from bone marrow and periosteum were comparable. The bone marrow and periosteum should be a suitable source for MSC isolation. The growth kinetics of MSCs derived from adipose tissue was lower than the other sources. Adipose tissue can be used as an alternative source as it is readily available and dispensable.

Keywords: Mesenchymal stem cells, Bone marrow, Periosteum, Adipose tissue, Growth kinetics, Population doubling time, Colony forming units